The major thrusts of our program are related to cytomegalovirus (CMV) infections. We are pursuing our original demonstration of CMV in semen and We have begun several prospective epidemiological studies. We are also developing what we believe will be a very useful and important animal model for veneral transmission of CMV. Our investigations of CMV in transplantation include studies of transfusion, organ transplantation, tumor and skin trannsplants. We seek in these studies and in those of organ explants and CMV core antigens to further understand the establishment and reactivation of latent virus. During the coming year we intend to: 1. Continue our prospective study of pregnant adolescents and sexual partners. 2. Initiate epidemiologic studies of genital CMV infections within the homosexual community and along renal transplant recipients. 3. Enlarge our use of the mouse model of sexual transmission of CMV. 4. Further elaborate the mutual interaction of CMV infections and the host immune response. 5. Test CMV core antigens in various test procedures. BIBLIOGRAPHIC REFERENCES: Lang, D.J., Kummer, J.F.: Cytomegalovirus in Semen: Observations in selected populations. J. Inf. Dis. 132: 472, 1975. Cheung, K.S., Smith, H.M., Lang, D.J.: The transmission of cytomegalovirus (CMV) in blood transfusion: A murine model. Ped. Research 9: 339, 1975.